Frequency-adjusting means for high-frequency signaling systems



C. L. DAVIS March 17, 1931.

FREQUENCY ADJUSTING MEANS FOR HIGH FREQUENCY SIGNALING SYSTEMS Filed March 7, 1929 INVENTOR. 00M 9 wow/i0, Y 5. am W ATTORN Y .k 2 l k T Patented Mar. 17, 1931' u-Niran PATENT: OFFI cnnsrnnn DAVIS, onwasnme-ron, msrarcr or comnmu, assranonro W'IBED RADIO, 1nd,, or NEW Yonx, 1;. Y.

, A CORPORATION OF DELAWARE rnnou sncynnrus'rrne Means roa nien-rnnotrnncy s reiunmo sYs'rmls lpplicationfiled larch 7,

My invention relates to high frequency 'sifgl naling systems in general and more'speci cally to'apparatus employedin radio trans-'- mitters and receivers.

' An ob'ect ofmy'invention is to provide certain improvements in frequency calibration of radio receivers and transmitters.

. Another objectof my invention is to provide an improvedfrequency adjusting system forc-hi'gh frequency apparatus.

Still 'another'object of my inventionis to provide an improved frequency indicating system which is of compact form andappli cable for installation on radio broadcast transmittersandreceivers. v I I A furtherobject of my invention is to provide aconstruction of control unit inser'table:

in the control panel of a frequency adjustingapparatus which unit contains a rotatable micrometer adjustingdevlce and means for magnifying the calibrations on the rotary indi'cator which is housed unit.

My invention can be better understood from the specification hereinafter following within the control by reference to the accompanying drawings,

wherein a 1 Figure 1 is an elevational viewshowing the control unit of-m'ydnvention inserted in the panel of the :frequency'control apparatus;

Fig. 2 is a cross-sectional view'through the 1 ciated with such means is provided a dial which is calibrated in frequency or merely in arbitrary numbers from which the fre quency may be determined. It is diflicult to provide an accurately calibrated disk or dial from which the frequency may be ascertained rate reading thereof 1929. Serial Io. 845,167. g without designing a dial of large size. This dialthen is subject to inaccuracies caused by temperature changes, mechanical imperfections and inabillty of theoperator to roperly and accurately determine the cali rationindicated at a particular adjustment; In my improvements in high freguency signaling slystems I provide certain eatures whereby t e frequency adjustment of the hi h frequency apparatus may be accurate y and 'readily determined and whereby the freuency is accurately and readily determined rom the calibration without needless inter polation. I

The control unit of my invention is a precision instrument which 1s adapted to be connected to the rotary adjusting shaft of a frequency control apparatus for imparting roitary movement to the control shaft and simultaneously moving an indicator which is observable through a sight openin in the front of the control unit. The call rations on the dial within the control unit are observable through the sight opening and in order to increase the precision with which the control unit may be adjusted, I provide a magnifying device adjustably positioned within the sight opening to enlarge the calibrated divisions on the dial and permit the more accu- In Fi 1 of the drawings, I have illustrated t e frequency control apparatus as mounted behind an instrument panel 3 throu h which the control unit which is housed within a shell 8 is mounted. The

shell 8 may be of phenol composition, metal,

or other suitablem'aterial and provides a housing in which the movable parts of the control mechanism of my invention are mounted. The shell 8. has an inwardly directed flange portion 8?) at the rear thereof providing securing means for the rear closure plate 1 which'issecured to the inwardly engaging flange 86 by suitable screws 1a. The shell 8 is provided with a cylindrical projection 8a in the front thereof which receives the lens carrier 2 carrying lens 2a and having spring fingers 2Z2 projecting therefrom and gripping the interior walls of the cylindrical projection 8a in such manner that the lens may be shifted toward or away from the calibrated dial within .the'control unit. The rear closure plate 1 is provided with an inwardly projectingbearing portion 1?) through which the rotary shaft 4 is journaled. The gear 6 is connected to rotary shaft and'car- .ries on the front thereof the calibrated dial The dial '5fis rotatable in such manner that the peripheral portion thereof passes behind .the cylindrical which I have indicated at 5.

projection 8a in the shell '8 in such manner that the projection 8a functions asza sighting window with respect to the calibrations 1 5 011 the rotatable dial. The calibrated dial 5 is rotated through a system of gears which I have designated at 11, 1 2, 15, and 17. vThe gear 11 is carried by rotatable adjusting shaft 10 which is journaled in the bearing portion 80 of the shell 8 ofthe control unit, the control knob 9 being connected'to the shaft 10. Gear 12 is p'ivotally-mounted in position means of screw 14.- on the interior wall ofathe shell 8. Gear '15 is rotatably mounted on screw 16 which extends into the shell8. The

gear .15 .is interconnected by means :of rotatable sleeve 18 with-thegear-l7 so Ithatmotion imparted-to gear 15 is transmitted to gearl"? which meshes with the gear 6 which carries calibrated dial 5. Motion imparted to .adjustable knob 9 is therefore "reduced ;and a slow movement impartedto gear .6 for transmitting a corresponding movement to v,sha ft 4. A coupling device 7 is provided for finterconnectin thecontrol unitwith-therotary shaft of a requency adjusting apparatus. The fine calibrations engraved on 'dial .5 are enlarged to a readily readable size the lens 2a which is shifted to the proper position with respect to the calibrations on the dial-"5. A hairline may be drawn on the lens or suspended within the cylindrical projection 8a in order that .readings may betaken for the proper dial setting. I V

The advantages of the improvements in high frequency signaling systems of :my invention are numerous. In the employment of extremely high frequency electrical energy it is essential that the frequency adjusting means be accurately calibrated. To interpolation between two numbers or degrees of the calibration is diflicult and accurate determination of the frequency adjustment from the calibrated indicating means is nearly ,im-possible. This is due to the inaccuracy ofcalibration, mechanical features of construction or .minuteness of the calibrated portion. En-

jlarging the calibrated drum or dial by {enlarging its physical dimensions has previously been referred toand obviously is notadesirable feature. By employing an enlarging lens in the manner described, the .actual physical enlargement of the calibrated portion with its accompanying disadvantages is avoided, While the dial or drum is o tically enlarged to the observer. 'The cali ration greases may be so small as-nottot-be visible with the eye-alone. The features of:micro-mechanical ,adjustingmeans whereby efiorts'are made to secure.approximateindications is far inferior to the foregoing improvementsno'f my invention. iPhysicalexpansion ofgtheidial or drum *dueitoan increase in temperature is greatly .-=casing .insertable 1into.;an instrument panel, a

rotatable-shaftimember journaledin each side of saidcas'ing, gears "carried 'i by each of said rotatable shaft menibers,a-calibrated dialcar- ;rLied -=by:the geari'on one "of. saidrotatable shaft vmembersand movable within saidcasing, an :ad'just ing knob connected to the other of --sai'd;=ro tata'ble shaft "members, a motion reduction gear interconnecting said aforesaid gears whereby angular movement imparted it-osaid adjusting knob producessmaller angu- ..la-r;movement of said calibrated dial, and a sightingwindow carried :by said'casing in a position adjacent said:adjustngknob-for obger-ilring the -;.cal ibrations on .said calibrated 1a '2. Acontrol unit insertable into an instruanent panel comprising-an encl'osing casing, v:means. connect ible to an instrument adjusting shaft extending'throughthe rear of said casing, van adjustable :knob "having a control shaft extending through the front of said 'casing,laz-motion reduction gear interconnectling said shafts, :a calibrated dial rotatable within :said casing, and :a sightin aperture rcarried byjthepfront of said casing gorobservingthecalibrations:onxsaidd ia-l in accordance with -;the movement imparted thereto by rotation of saidad justing knob.

In testimony whereof l .aifix my si 1 ature.

' CHESTER Li D V'IS. 

